全文获取类型
收费全文 | 9785篇 |
免费 | 545篇 |
国内免费 | 40篇 |
专业分类
耳鼻咽喉 | 40篇 |
儿科学 | 188篇 |
妇产科学 | 182篇 |
基础医学 | 1307篇 |
口腔科学 | 446篇 |
临床医学 | 813篇 |
内科学 | 2653篇 |
皮肤病学 | 255篇 |
神经病学 | 994篇 |
特种医学 | 297篇 |
外科学 | 1172篇 |
综合类 | 26篇 |
一般理论 | 2篇 |
预防医学 | 458篇 |
眼科学 | 131篇 |
药学 | 559篇 |
中国医学 | 27篇 |
肿瘤学 | 820篇 |
出版年
2024年 | 8篇 |
2023年 | 72篇 |
2022年 | 154篇 |
2021年 | 290篇 |
2020年 | 158篇 |
2019年 | 230篇 |
2018年 | 272篇 |
2017年 | 217篇 |
2016年 | 224篇 |
2015年 | 277篇 |
2014年 | 384篇 |
2013年 | 475篇 |
2012年 | 767篇 |
2011年 | 788篇 |
2010年 | 411篇 |
2009年 | 372篇 |
2008年 | 654篇 |
2007年 | 672篇 |
2006年 | 594篇 |
2005年 | 641篇 |
2004年 | 554篇 |
2003年 | 496篇 |
2002年 | 477篇 |
2001年 | 100篇 |
2000年 | 87篇 |
1999年 | 90篇 |
1998年 | 107篇 |
1997年 | 75篇 |
1996年 | 74篇 |
1995年 | 68篇 |
1994年 | 57篇 |
1993年 | 40篇 |
1992年 | 48篇 |
1991年 | 48篇 |
1990年 | 47篇 |
1989年 | 46篇 |
1988年 | 30篇 |
1987年 | 36篇 |
1986年 | 34篇 |
1985年 | 25篇 |
1984年 | 23篇 |
1983年 | 24篇 |
1982年 | 18篇 |
1981年 | 8篇 |
1980年 | 18篇 |
1979年 | 9篇 |
1976年 | 9篇 |
1974年 | 8篇 |
1970年 | 6篇 |
1968年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Vaiano A Claudio Traino A Boni G Grosso M Lazzeri P Colato C Davì MV Francia G Lazzeri M Mariani G Ferdeghini M 《Nuclear medicine communications》2007,28(3):215-223
OBJECTIVE: In thyroidectomized patients, increased levels of thyroid stimulating hormone (TSH) are necessary to maximize I uptake. Traditionally, this has been achieved by withdrawing L-thyroxine (L-T4) for 4-6 weeks, inducing hypothyroidism in patients. The availability of a genetically engineered version of the recombinant human TSH (rh-TSH) provides an alternative tool to enhance the TSH serum level without inducing hypothyroidism. In this paper the I remnant and red-marrow doses calculated in differentiated thyroid cancer (DTC) patients pre-treated with rh-TSH are compared to those calculated in patients in hypothyroidism induced by L-T4 withdrawal. METHODS: Forty-six DTC patients, submitted to I ablative therapy, were randomly divided in group A (pre-treated with rh-TSH) and group B (treated after L-T4 withdrawal for 30 days). The red-marrow absorbed dose per unit administered activity and the remnant cumulated activity per unit administered activity were calculated for both groups. RESULTS: The red-marrow dose in 17 rh-TSH treated patients is 0.06+/-0.02 mGy.MBq; that in 14 hypothyroid patients is 0.09+/-0.03 mGy.MBq (two-tailed unpaired t-test P=0.003). The remnant cumulated activity per unit administered activity in 10 rh-TSH treated patients is 0.9+/-0.8 h; that calculated in 21 hypothyroid patients is 1.55+/-1.05 h (two-tailed unpaired t-test P=0.063). This last result is mainly due to the difference between the maximum uptake (U) in rh-TSH (U=0.01+/-0.01) and hypothyroid patients (U=0.03+/-0.02) (two-tailed unpaired t-test P=0.019). CONCLUSION: The rh-TSH pre-treated patients seem to have a lower uptake compared to those in hypothyroidism induced by L-T4 withdrawal. On the other hand their red-marrow absorbed dose seems to be lower. 相似文献
992.
Riesenman PJ Mendes RR Mauro MA Farber MA 《Cardiovascular and interventional radiology》2007,30(5):1025-1028
Aneurysmal lesions of the external carotid artery are extremely rare. A case is presented of a 3.8 cm right external carotid
artery pseudoaneurysm treated by transluminal exclusion using an endovascular stent-graft. Following stent-graft placement,
complete occlusion of the aneurysmal sac and main vessel lumen patency was successfully demonstrated. This report demonstrates
the technical feasibility of utilizing stent-grafts to treat aneurysmal lesions involving the external carotid artery. 相似文献
993.
Alves GG Marinho-Carvalho MM Atella GC Silva-Neto MA Sola-Penna M 《Anais da Academia Brasileira de Ciências》2007,79(1):53-62
6-Phosphofructo-1-kinase (phosphofructokinase; PFK) activity from Rhodnius prolixus, a haematophagous insect which is usually a poor flyer, was measured and compared in two metabolically active tissues - flight muscle and fat body. The activity of this important regulatory glycolytic enzyme was much more pronounced in muscle (15.1 +/- 1.4 U/mg) than in fat body extracts (3.6+/-0.4 U/mg), although the latter presented higher levels of enzyme per protein content, as measured by western-blotting. Muscle extracts are more responsible than fat body to ATP and fructose 6-phosphate, both substrates of PFK. Allosteric regulation exerted by different effectors such as ADP, AMP and fructose 2,6-phosphate presented a singular pattern for each tissue. Optimal pH (8.0-8.5) and sensitivity to pH variation was very similar, and citrate was unable to inhibit PFK activity in both extracts. Our results suggest the existence of a particular PFK activity for each tissue, with regulatory patterns that are consistent with their physiological roles. 相似文献
994.
Frego M Bianchera G Angriman I Norberto L Pilon F Polese L Scarpa M Ruffolo C Corso S De Zolt P 《Annali italiani di chirurgia》2007,78(4):277-281
Worldwide literature review from PubMed indicate that progress has been made in first aid assistance, diagnosis and treatment of ruptured abdominal aortic aneurysms, which led to a reduced operative mortality. Nevertheless, ruptured aneurysms may present atipically in about half of the cases, thus leading to an initially uncorrect diagnosis up to 25% of cases. Mean survival interval from onset of symptoms and death is 10-14 hours, thus indicating that time exists to consider the new imaging techniques in 80% of patients, particularly the TC multislice. This, when is strategically located close to the emergency or the operative room, can rapidly allow a correct diagnosis and provide an accurate morphological evaluation, thus enabling the surgeon to plan the most adequate treatment with open or endovascular repair. 相似文献
995.
Mortality after bariatric surgery: analysis of 13,871 morbidly obese patients from a national registry 总被引:3,自引:0,他引:3 下载免费PDF全文
Morino M Toppino M Forestieri P Angrisani L Allaix ME Scopinaro N 《Annals of surgery》2007,246(6):1002-7; discussion 1007-9
OBJECTIVE: To define mortality rates and risk factors of different bariatric procedures and to identify strategies to reduce the surgical risk in patients undergoing bariatric surgery. SUMMARY BACKGROUND DATA: Postoperative mortality is a rare event after bariatric surgery. Therefore, comprehensive data on mortality are lacking in the literature. METHODS: A retrospective analysis of a large prospective database was carried out. The Italian Society of Obesity Surgery runs a National Registry on bariatric surgery where all procedures performed by members of the Society should be included prospectively. This Registry represents at present the largest database on bariatric surgery worldwide. RESULTS: Between January 1996 and January 2006, 13,871 bariatric surgical procedures were included: 6122 adjustable silicone gastric bandings (ASGB), 4215 vertical banded gastroplasties (VBG), 1106 gastric bypasses, 1988 biliopancreatic diversions (BPD), 303 biliointestinal bypasses, and 137 various procedures. Sixty day mortality was 0.25%. The type of surgical procedure significantly influenced (P < 0.001) mortality risk: 0.1% ASGB, 0.15% VBG, 0.54% gastric bypasses, 0.8% BPD. Pulmonary embolism represented the most common cause of death (38.2%) and was significantly higher in the BPD group (0.4% vs. 0.07% VBG and 0.03% ASGB). Other causes of mortality were the following: cardiac failure 17.6%, intestinal leak 17.6%, respiratory failure 11.8%, and 1 case each of acute pancreatitis, cerebral ischemia, bleeding gastric ulcer, intestinal ischemia, and internal hernia. Therefore, 29.4% of patients died as a result of a direct technical complication of the procedure. Additional significant risk factors included open surgery (P < 0.001), prolonged operative time (P < 0.05), preoperative hypertension (P < 0.01) or diabetes (P < 0.05), and case load per Center (P < 0.01). CONCLUSIONS: Mortality after bariatric surgery is a rare event. It is influenced by different risk factors including type of surgery, open surgery, prolonged operative time, comorbidities, and volume of activity. In defining the best bariatric procedure for each patient the different mortality risks should be taken into account. Choice of the procedure, prevention, early diagnosis, and therapy for cardiovascular complications may reduce postoperative mortality. 相似文献
996.
Hiroki Nakata Kiwako Sakamoto Antonio Ferretti Mauro Gianni Perrucci Cosimo Del Gratta Ryusuke Kakigi Gian Luca Romani 《Neuroscience letters》2009
Inhibiting inappropriate behavior and thoughts in the current context is an essential ability for humans, but the neural mechanisms for response inhibitory processing are a matter of continuous debate. The aim of this event-related functional magnetic resonance imaging (fMRI) study was to evaluate the negative blood oxygen level dependent (BOLD) effect on inhibitory processing during go/no-go paradigms. Fifteen subjects performed two different types of somatosensory go/no-go paradigm: (1) button press and (2) count. Go and no-go stimuli were presented with an even probability. We observed a common negative activation during Movement No-go and Count No-go trials in the right SFG, corresponding to BA 8. These findings suggest that the right SFG region was responsible for the negative BOLD effect on inhibitory processing, which was independent of the required response mode. We hypothesized several possible explanations for the deactivation of the SFG during no-go trials. 相似文献
997.
William Vermi Silvia Lonardi Mauro Morassi Cristina Rossini Regina Tardanico Marina Venturini Raffaella Sala Angela Tincani Pietro Luigi Poliani Pier Giacomo Calzavara-Pinton Lorenzo Cerroni Amerigo Santoro Fabio Facchetti 《Immunobiology》2009,214(9-10):877
Recent evidences suggest a significant role of Plasmacytoid dendritic cells (PDC) role in the pathogenesis of lupus erythematosus (LE) via production of type I IFN. Taking advantage on the availability of multiple reagents (CD123, BDCA2, and CD2ap) specifically recognizing PDC on fixed tissues, we investigated the occurrence of PDC in a cohort of 74 LE patients. The large majority of LE biopsies (67/74; 90.5%) showed cutaneous infiltration of PDC. PDC were more frequently observed (96.4 vs 72.2) and numerous in cutaneous LE compared to systemic LE (SLE) and correlated with the density of the inflammatory infiltrate (r=0.40; p<0.001). PDC reduction in SLE might be related to a broader tissue distribution of this cellular population, as indicated by their occurrence in kidneys in 11 out of 24 (45.8%) cases studied. The distribution of cutaneous PDC showed two distinct patterns. More commonly, PDC were observed within perivascular inflammatory nodules in the dermis, associated with CD208+ mature DC and T-bet+ cells [D-PDC]. A second component was observed along the dermal-epithelial junction [J-PDC], in association with cytotoxic T-cells in areas of severe epithelial damage. Notably, chemerin reactivity was observed in 64% of LE biopsies on endothelial cells and in the granular layer keratinocytes. Cutaneous PDC in LE strongly produced type I IFN, as indicated by the diffuse MxA expression, and the cytotoxic molecule granzyme B.This study confirms cutaneous PDC infiltration as hallmark of LE. The topographical segregation in D-PDC and J-PDC suggests a novel view of the role of these cells in skin autoimmunity. 相似文献
998.
Del Gaudio C Bianco A Folin M Baiguera S Grigioni M 《Journal of biomedical materials research. Part A》2009,89(4):1028-1039
Electrospinning is a valuable technique to fabricate fibrous scaffolds for tissue engineering. The typical nonwoven architecture allows cell adhesion and proliferation, and supports diffusion of nutrients and waste products. Poly(epsilon-caprolactone) (PCL) electrospun membranes were produced starting from 14% w/v solutions in (a) mixture 1:1 tetrahydrofuran and N,N-dimethylformamide and (b) chloroform. Matrices made up of randomly arranged uniform fibers free of beads were obtained. The average fiber diameters were (a) 0.8 +/- 0.2 microm and (b) 3.6 +/- 0.8 microm. PCL matrices showed the following tensile mechanical properties: tensile modulus (a) 5.0 +/- 0.7 MPa (b) 6.4 +/- 0.2 MPa, yield stress (a) 0.55 +/- 0.06 MPa (b) 0.43 +/- 0.02 MPa, and ultimate tensile stress (a) 1.7 +/- 0.2 MPa and (b) 0.8 +/- 0.1 MPa. The ultimate strain ranged between 300% and 400%. Cytotoxicity of electrospun membranes was continuously evaluated by means of electric cell-substrate impedance sensing technique using human umbilical vein endothelial cells (HUVEC). PCL matrices resulted free of toxic amounts of contaminants and/or process by-products. In vitro studies performed by culturing HUVEC on micrometric and submicrometric fibrous mats showed that both structures supported cell adhesion and spreading. However, cells cultured on the micrometric network showed higher vitality and improved interaction with the polymeric fibers, suggesting an increased ability to promote cell colonization. 相似文献
999.
1000.
Samuel Aguiar Junior Fábio de Oliveira Ferreira ; Benedito Mauro Rossi érika Maria Monteiro Santos Jo?o Victor Salvajoli Ademar Lopes 《Clinics (S?o Paulo, Brazil)》2009,64(11):1059-1064